Guiana dolphin is the top predator of highest toxicological concern in Brazil and many studies on levels of persistent, bioaccumulative, and toxicant (PBT) pollutants have been performed on the species ... [more ▼]

Guiana dolphin is the top predator of highest toxicological concern in Brazil and many studies on levels of persistent, bioaccumulative, and toxicant (PBT) pollutants have been performed on the species. However, due to high costs of the analyses, only one investigation comprised the determination of dioxins and related compounds (DRCs) in Guiana dolphin tissues. The dioxin responsive-chemically activated luciferase gene expression (DR-CALUX ) cell bioassay was used in the present study for the analyses of hepatic samples from 28 male Guiana dolphins in order to screen estuarine environments for DRCs, comprising three regions (Northeastern, Southeastern, and Southern) and four states [Parana´ (PR), Rio de Janeiro (RJ), Espı´rito Santo (ES), and Ceara´ (CE)] of Brazil. High bioanalytical equivalent (BEQ) concentrations [dioxins (pg BEQ/g lipid)] were found, varying from 1.94 to 15.6 pg BEQ/g. A significant negative correlation between BEQ concentrations and total length was found in Guiana dolphins from Brazil (all analysed dolphins). This pattern also was verified for RJ state, pointing to (1) chemically induced developmental disruption or to (2) increasing efficiency of the detoxifying activity with the growth of the animal. Comparison was performed with literature data and significantly higher BEQ levels were found in Brazilian Guiana dolphins than in those reported for North Sea harbour porpoises. Higher levels were found in Southeastern (the most PBT-contaminated area of the country) than in Southern region. However, it is not possible to affirm that Guiana dolphins are more contaminated by DRCs in SE than in S region, because individuals were lengthier in S than in SE region. Our results seem to have mirrored dolphin exposure to PCBs in Brazil according to the literature. Further studies are required for investigating the hypotheses 1 and 2 mentioned above. [less ▲]

To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ13C) and nitrogen (δ15N) isotopes in muscle samples of the following 10 delphinid species: Sotalia ... [more ▼]

To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ13C) and nitrogen (δ15N) isotopes in muscle samples of the following 10 delphinid species: Sotalia guianensis, Stenella frontalis, Tursiops truncatus, Steno bredanensis, Pseudorca crassidens, Delphinus sp., Lagenodelphis hosei, Stenella attenuata, Stenella longirostris and Grampus griseus. We also compared the δ13C and δ15N values among four populations of S. guianensis. Variation in carbon isotope results from coast to ocean indicated that there was a significant decrease in δ13C values from estuarine dolphins to oceanic species. S. guianensis from Guanabara Bay had the highest mean δ13C value, while oceanic species showed significantly lower δ13C values. The highest δ15N values were observed for P. crassidens and T. truncatus, suggesting that these species occupy the highest trophic position among the delphinids studied here. The oceanic species S. attenuata, G. griseus and L. hosei had the lowest δ15N values. Stable isotope analysis showed that the three populations of S. guianensis in coastal bays had different δ13C values, but similar δ15N results. Guiana dolphins from Sepetiba and Ilha Grande bays had different foraging habitat, with specimens from Ilha Grande showing more negative δ13C values. This study provides further information on the feeding ecology of delphinids occurring in southeastern Brazil, with evidence of distinctive foraging habitats and the occupation of different ecological niches by these species in the study area. [less ▲]

Blubber samples from three delphinid species (false killer whale, Guiana and rough-toothed dolphin), as well as liver samples from franciscana dolphins were analyzed for dioxins and related compounds ... [more ▼]

Blubber samples from three delphinid species (false killer whale, Guiana and rough-toothed dolphin), as well as liver samples from franciscana dolphins were analyzed for dioxins and related compounds (DRCs). Samples were collected from 35 cetaceans stranded or incidentally captured in a highly industrialized and urbanized area (Southeast and Southern Brazilian regions). Dioxin-like PCBs accounted for over 83% of the total TEQ for all cetaceans. Non-ortho coplanar PCBs, for franciscanas (82%), and mono-ortho PCBs (up to 80%), for delphinids, constituted the groups of highest contribution to total TEQ. Regarding franciscana dolphins, significant negative correlations were found between total length (TL) and three variables, ΣTEQ-DRCs, ΣTEQ-PCDF and ΣTEQ non-ortho PCB. An increasing efficiency of the detoxifying activity with the growth of the animal may be a plausible explanation for these findings. This hypothesis is reinforced by the significant negative correlation found between TL and PCB126/PCB169 concentration ratio. DRC concentrations (ng/g lipids) varied from 36 to 3006, for franciscana dolphins, as well as from 356 to 30776, for delphinids. The sum of dioxin-like and indicator PCBs varied from 34662 to 279407 ng/g lipids, for Guiana dolphins from Rio de Janeiro state, which are among the highest PCB concentrations ever reported for cetaceans. The high concentrations found in our study raise concern not only on the conservation of Brazilian coastal cetaceans, but also on the possibility of human health problem due to consumption of fish from Brazilian estuaries. [less ▲]

Liver samples from 51 cetaceans, comprising 10 species, stranded between 1994 and 2006 in a highly industrialized and urbanized region in Southeast Brazil, were analyzed for polybrominated diphenyl ethers (PBDEs) and methoxylated-PBDEs (MeO-PBDEs). A concentration range of PBDEs (3-5960 ng/g lw) similar to that observed in Northern Hemisphere dolphins was found. MeO-PBDE concentrations in continental shelf (CS) dolphins from Brazil are among the highest detected to date in cetaceans (up to 250 µg/g lw). Higher [Sigma]MeO-PBDE concentrations were measured in CS and oceanic dolphins than in estuarine dolphins. The [Sigma]PBDE/[Sigma]MeO-PBDE ratio varied significantly ranging from a mean value of 7.12 to 0.08 and 0.01 for estuarine, CS and oceanic species, respectively. A positive correlation was observed between [Sigma]PBDE and year of stranding of male estuarine dolphins (Sotalia guianensis), which suggests temporal variation in the exposure. Placental transfer of organobrominated compounds was also evidenced in S. guianensis. [less ▲]

Perfluorooctane sulfonate (PFOS) and other perfluoroalkyl compounds (PFCs) were measured in liver samples from 29 marine tucuxi dolphins from Rio de Janeiro state (RJ), Brazil. PFC measurement combined liquid chromatography and mass spectrometry, using a CapLC system connected to a Quadrupole- LIT mass spectrometer. PFOS was the only PFC detected and it was so in all samples. PFOS concentrations (ng ·g-1 dw) of dolphins (n)23) from the highly contaminated Guanabara Bay (in RJ) varied between 43 and 2431 as well as between 76 and 427 from areas of RJ other than the quoted bay (n ) 6). Concentrations of three fetuses and one neonate varied between 664 and 1590. Fetus/mother ratios were calculated in two situations (2.75 and 2.62). It seems that mother-to-calf transference plays important role for relationships between PFOS and age. When a one-year-old male calf presenting 2431 ng ·g-1 dw was excluded from the test, significant correlations were observed between PFOS concentrations and both age and total length. Despite the placental transference, PFOS concentrations were not significantly lower in females than in males. PFOS levels in marine tucuxi dolphins from Guanabara Bay are among the highest detected to date in cetaceans, andthismayrepresentathreat to the small population concerned. [less ▲]

The main objective of the present study was to determine the current concentrations of PCDDs, PCDFs and PCBs in dolphins from a region of high industrialization and urbanization in the Southern Hemisphere ... [more ▼]

The main objective of the present study was to determine the current concentrations of PCDDs, PCDFs and PCBs in dolphins from a region of high industrialization and urbanization in the Southern Hemisphere. Since most of these compounds biomagnify in food chains and changes in ratios of stable isotopes of nitrogen (15N/14N) have been used to elucidate trophic relationships 7, measurements of these isotopes have been carried out in marine tucuxi dolphins and their prey in Guanabara Bay. Stable isotopes were measured, firstly, to quantitatively assess the trophic level of the dolphin, and, secondly, to provide information for future human risk assessment investigations related to fish consumption [less ▲]

The main objective of the present study was to determine the current concentrations of organobrominated compounds in odontocete species from a highly industrialized and urbanized region in the Southern ... [more ▼]

The main objective of the present study was to determine the current concentrations of organobrominated compounds in odontocete species from a highly industrialized and urbanized region in the Southern Hemisphere. [less ▲]

The main objective of the present study was to determine the current concentrations of PFOS in dolphins from neritic and oceanic waters of a region of high industrialization and urbanization in the ... [more ▼]

The main objective of the present study was to determine the current concentrations of PFOS in dolphins from neritic and oceanic waters of a region of high industrialization and urbanization in the Southern Hemisphere. Since stable carbon isotopes can be used to point out relative contributions to the diet of different potential primary sources in trophic networks, indicating for example the inshore versus offshore contribution to food intake 7,8, stable carbon isotope measurements were carried out in the same dolphins in order to clarify inter-species differences. [less ▲]